1. Field of the Invention
The present invention relates to a device for detecting an obstacle on a path forward of a running vehicle.
2. Description of the Prior Art
An obstacle detection device has been known that scans a specific area extended forward of a running vehicle to detect an obstacle. Such a device is disclosed in Japanese Patent Publication No. 3-6472, published for opposition in 1990.
In such an obstacle detection device, if a plurality of obstacles are detected within the specific area, it is necessary to assess how dangerous each of the obstacles is so that a vehicle control, such as production of an alarm, a braking control and steering control for avoiding the obstacles can be made afterward.
If the obstacle is moving in the specific area, a rank of danger changes. Therefore, it is necessary to trace the moving obstacle in order to make a proper assessment. However, a conventional device cannot satisfy this requirement.
Japanese Patent Public Disclosure No. 2-287180, laid open to the public in 1990, discloses a device for switching a direction of a radiation beam for detecting an obstacle in accordance with a moving direction of the vehicle in a turning action.
However, the conventional device detects installations by the road, such as a guardrail or a sign pole, as an obstacle so that a control for avoiding a true obstacle is confused.